There's nothing silly or corny about the effects. They are highly effective and very much ahead of their time. The show would have been even better if they had continued to use them instead of falling into standard, formulaic setups.
Even though I don't hate "zoom" effects, one thing I've always liked about DAGGERS OF THE MIND has to do with the scene where Joe is leaning toward Nicky and Lily's car with that umbrella, and Nicky realizes it's Sir Roger's, and he gives that look like he wants to cry! A "zoom" would have underlined that too much, but without it the look he gives really creeps up on you. (Actually, I don't know how many times I saw the episode BEFORE noticing it.)
I'm confused as to who Joe is, but if it's Don Knight, he's an underrated gem. He was also the mechanic in Étude in Black who looked at Columbo's car and said "There are limits".
But aside from his two Columbo roles, he plays the lead alongside Laurence Harvey in the famous Night Gallery episode The Caterpillar. He is phenomenal. He pushes and provokes Harvey's lust to overcome his moral judgement and he causes a disaster in a way that only a true idiot can.
It was some of the most brilliant acting I've ever seen from both men and I highly recommend the 20 minute episode which is available on Hulu but not Netflix.